Incinerator apparatus



Dec. 17, 1957 D. H. HENDERSON 2,816,519

INCINERATOR APPARATUS Original Filed Dec. 18, 1952 5 Sheets-Sheet 1 IN V EN TOR.

0:48:07 h! firyotlfsazv Dec. 17, I957 D. H. HENDERSON INCINERATOR APPARATUS 5 Sheets-Sheet 2 Original Filed IN V EN TOR.

ATTO/f/VEYJ Dec. 17, 1957 D. H. HENDERSON 2,816,519

INCINERATOR APPARATUS Original Filed Dec. 18, 1952 5 Sheets-Sheet 3 T9 5 I INVENTOR.

D. H. HENDERSON INCINERATOR APPARATUS Original Filed Dec. 18, 1952 Dec. 17, 1957 5 Sheets-Sheet 5 United States Patent 6 IN CINERATOR APPARATUS Delbert H. Henderson, Artesia, Calif. Application December 12, 1956, Serial No. 627,915 15 Claims. (Cl. 110-18) This invention relates to new and useful improvements in chimney-fed incinerators, and to various combinations of dehydrators and burners for use in incinerators.

This application is a continuation of my copending application Serial No. 326,698, filed December 18, 1952, now abandoned which in turn was a continuation-in-part of my copending application Serial No. 157,808, filed April 24, 1950, and now Patent No. 2,690,720, for Safety Dehydrator Ventilator.

It is a well known fact that many incinerators constructed and used in dwelling houses, apartment houses, hospitals, store buildings, and the like, are provided with a gas burning attachment to assist in consuming the variousmaterials to be incinerated.

In general, such gas burners have proved to be a nuisance because of the damage done to the grates and other parts of the incinerators, and also because of the great risk of back-up of fumes or raw gas, creating a risk of asphyxiation or possibly an explosion.

In case the gas burners are installed below the grates, the heat from the burners will cause the grates to Warp and break. In case such grates become clogged or obstructed with ashes or garbage, the fumes from the burner cannot go through the rubbish or obstructions on the grates, with the result that these fumes will escape out into the room where the incinerator is located.

In the event the gas flame is extinguished, either because of lack of oxygen in the ash pit, or because the flame is blown out, or for any other reason, the raw gas will continue to flow and back-up, thus creating a serious explosion hazard. In the event the burner is installed above the grates, it will sometimes become completely surrounded by Waste products which are too damp or wet to burn, thus extinguishing the flame and creating the same hazards mentioned above. Many other difiiculties have been encountered with the use of gas burners in incinerators.

In chimney-fed incinerators, sometimes the chimney or feed flue becomes completely obstructed with trash which will not go on down the chimney or flue, thus creating a very serious hazard in case the conventional gas burning incinerator is lit. If the combustible material down below begins to burn, there is no free escape of the products of combustion and smoke comes out into the building through the various doors intended for the feeding of trash. If the gas burner is completely surrounded by trash so that it does not receive enough air, sometimes the gas does not light resulting in a dangerous and explosive mixture occurring in the chimney or feed flue. In any case, whether the trash is lit by the use of a gas burner or otherwise, there often results a tremendous fire up the entire length of the chimney or feed flue with very high temperatures which may be dangerous to surrounding structure or in any case is hard on the chimney or flue lining due to the high temperature.

As a matter of fact, many owners are actually afraid to use the gas burner, and in some municipalities such 2,816,519 Patented Dec. 17, 1957 burner use is prohibited altogether. Furthermore, failure to use the gas burner always results in imperfect combustion, which means that instead of removing a small volume of clean ashes, there is always a large quantity of ashes and partly burned garbage to be removed, which invariably has a bad odor, thus creating a health problem.

An object of my invention, then, is to provide a combination of features which, when installed in an incinerator and its coacting chimney, will make such incinerator much more serviceable than in the past.

One of these features is a dehydrator using natural, artificial, or bottled gas, or using fuel oil, or using electricity as a source of heat. This dehydrator provides sufficient heating area to dry out the trash and to burn it after it is dried. It is also arranged in such a way that it cannot become clogged so as to prevent the source of heat from coming into proper contact with the trash.

Another feature of my invention is a housing for the burner that not only dries out wet trash, such as garbage, but which ventilates both the ash pit and the combustion chamber to the chimney at all times.

Another feature of my invention is the provision of a specially constructed feed-flue in the chimney, extending from the combustion chamber to the top of the chimney, and of such a character that in general, an old chimney may be converted to my improved structure.

A further object of my invention is to provide a combination by-pass and burner that will never cause the grates to become warped or burned out, and which will further permit the easy disposal of glass, tin cans, etc. in the incinerator without interfering with the burner or with the operation of the grates.

A further object of my invention is the provision of burner arrangements especially adapted to carry out the above mentioned purposes.

A still further object of my invention is the provision of special dehydrator housings providing a large dehydrating area without interfering with the operation of the grates, and also arrangements of dehydrator housing which may be accommodated to furnaces of various size.

Advantages arising from the use of my invention include the following:

Preventing the risk of explosion in lighting a conventional incinerator in case the flame of the burner has gone out and the incinerator is filled with raw gas, my invention providing for the incinerator to be constantly lighted and ventilated.

The elimination of offensive garbage odors escaping from the ash pit in case the grates are plugged tight and making it possible for the incinerator to burn the refuse as it accumulates, running twenty-four hours a day if necessary.

Abatement of dense smoke from the top of the chimney, which ordinarily occurs when a twenty-four hour accumulation of garbage is burned at one time. My improved burner and method of operation reduces such dense smoke to a light haze, barely noticeable. My invention also minimizes the escape of fly-ash from the top of the chimney, as my invention maintains a fairly constant temperature at a minimum draft velocity. Prolongation of the life of the installation, or a reduction of maintenance costs by the provision of a constant low temperature fire in the combustion chamber as the rubbish accumulates, instead of a blast furnace once a day, the heat of which actually burns out the terra cotta liners in the chimney, the fire brick lining of the combustion chamber, and often melts or warps iron fittings about the furnace and chimney.

Reduction of the initial cost of building an incinerator, by incorporating my invention in a new installation, as my improved incinerator may be half as large and yet take care of the same load. Furthermore, high grade refractory lining is unnecessary, since ordinary fire brick will take care of the small amount of heat generated by the use of my invention.

Increasing the load of a given installation, that is to say, its capacity to incinerate a greater quantity of material. Sometimes the building may be enlarged without the necessity of building another incinerator, simply by installing my invention.

Reduction of heat, ash, smoke, fumes and fire at the top of the chimney, thus tremendously increasing the life of the wire mesh spark arrester at the top of the chimney, as well as the perforated feed-flue for trash.

Prevention of the accumulation of a large amount of trash extending a long distance up the chimney or feedflue with the attendant difliculties previously describe-:1.

Promotion of fire prevention, .as with my invention, properties will be safer, fewer sparks will escape from chimneys, fewer false. fire alarms, lower taxes and insurance rates, thus making flat roofs on apartment and office buildings more available for penthouse construction, roof gardens, sun bathing areas, and other similar uses, without the nuisance of smoke, fly-ash and sometimes red hot sparks from the chimney.

Finally, my invention reduces the risk of a large volume of fire billowing out through the hopper, or hoppers, when the same are opened for the insertion of trash, in case a heavy fire is burning in the incinerator, with the likelihood of burning someone, particularly if the spark guard at the top of the chimney should be blocked with paper or ashes at such a time. Also, my invention converts a conventional incinerator into a dehydrator which slowly dries out and then consumes garbage and like Wet materials.

Other objects and advantages of my invention will be apparent from the accompanying drawings and description and the essential features will be set forth in the appended claims.

In the drawings,

Fig. l is a fragmental perspective view of a portion of a chimney showin one type of a perforated feed-flue installed therein;

Fig. 2 is a perspective view of a spark guard for use at the top of the chimney;

Fig. 3 is a side elevational view of a chimney incorpo rating the feed-flue of Fig. l and a furnace having my improved dehydrator and burner installed, certain portions of the drawing being broken away in order to more clearly show the parts;

Fig. 4 is a cross-sectional view enlarged of the dehydrator housing and burner of Fig. 3;

Fig. 5 is a central sectional view through a furnace and chimney equipped with my invention and showing another embodiment of the feed-flue and chimney by-pass and another embodiment of the dehydrator housing and burner;

Fig. 6 is a transverse sectional view taken along the line 66 of Fig. 5;

Fig. 7 is a transverse sectional view enlarged taken along the line 7-7 of Fig. 5

Fig. 8 is a transverse sectional view taken along the line S 5 of Fig. 7;

Fig. 9 is a transverse sectional view through an incinerator furnace showing another modification of a dehydrator housing and bumer together with by-pass vent, a part being broken away to more clearly show the construction;

Fig. 10 is a top plan view of another modification of my dehydrator housing, showing the same equipped with an electrical heating unit;

Fig. ll is a perspective view partially broken away through another embodiment of an incinerator equipped with novel dehydrator housings;

Fig. 12 is a fragmental perspective view showing another embodiment of my dehydrator housing;

Fig. 13 is a side. elevational view of another embodiment of my invention showing a plural pass dehydrator housing;

Fig. 14 is a transverse sectional view of the same taken along the line 14-14 of Fig. 13;

Fig. 15 is a top plan view of still another embodiment of my improved dehydrator housing, the same being adjustable as to the length; while Fig. 16 is a transverse sectional view enlarged taken along the line 16-16 of Fig. 15.

Referring now to that form of my invention shown in Figs. 1 to 4 inclusive, a chimney 1 communicates at its base with the combustion chamber or furnace 10 of the incinerator. A feed-flue 2, perforated as shown at 3, is installed within the chimney 1, and inside of the refractory lining material 9 which, as usual, protects the brick of the chimney from intense heat. The feed-flue 2 is here shown of circular cylindrical form and may have one or more openings along its vertical height equipped with a feed door 3 so that trash may be passed down the feedflue to the incinerator chamber. The top of the chimney is provided with a spark arrester 4 and the top of the feed-flue, which extends above the chimney, is provided with a separate spark arrester 4A. An auxiliary spark arrester 5 covers the area between the lower end of the feed-flue and the chimney lining as shown in Fig. 3. The combustion chamber of the incinerator is provided with the usual ash pit 12, with bars or grates 13 forming the top of the ash pit, and a door 12A for removing the residue of the burned rubbish, or glass, cans, and other solid materials.

A dehydrator housing 15 extends generally horizontally across the bottom of the combustion chamber 10 and di-- rectly above the grates 13. The inner end of the housing 15 communicates with a vertical housing or vent 14, the upper end of which ext-ends upwardly a sufficient distance to clear the usual collection of trash resting on the grates 13. The lower end of the vent pipe 14 extends downwardly at 14a below the grates 13 so as to provide communication with the ash pit 12 below the grates. This vent pipe 14 serves to always carry off the products of combustion of the source of heat within the housing 15, even when the housing 15 is completely submerged in trash and substantially sealed off. The vent 14 also provides air from the ash pit to the furnace, chamber 10 above the trash so as to provide air for combustion and so as to insure that no explosive mixture is ever penned up in the ash pit 12.

Preferably, but not necessarily, one or more upstanding housing portions 1a may be provided with apertures near the top thereof, providing auxiliary or additional heating means for driving out and burning the garbage or refuse.

Means is provided for heating the dehydrator housing 15. In the present instance, this comprises a gas or fuel supply 6 leading to a short burner 7 of ball form having slots provided in its surface as outlets for the burning gas or fuel. A mixer 16 is provided with threads for securing the same Within the housing 15. This mixer has a direct connection with outside air so as to always provide sufiicient oxygen for the gas burner 7 to function efficiently. The flame issuing from the slots of the burner 7 passes along the horizontal housing 15 and heats the entire length of the housing. The housing 15 is provided with a plurality of apertures through which the heat from the burner escapes to hasten the drying out of any damp or Wet garbage or refuse in contact with or around such housing. There are perforations in the under surface of the horizontal housing 15 which are preferably larger than those in the top surface of the housing 15 so that in the event any particle from the combustion chamber drops through the upper holes, it will be sure to drop out through the bottom holes and not clog the burner.

In the operation of my improved incinerator, the control valve 11 in the supply pipe 6 is opened sufiiciently togive the proper amount of fuel suppliedto the burner 7.

Usually safety devices, not shown, are provided to shut off the gas if a pilot flame goes out. The burner is then ignited and may be allowed to burn at a low rate for a twenty-four hour period or it may be burned intermittently for a few hours during the three periods in the day when the most trash is fed to the incinerator. In any case, the entire housing 15 becomes very hot as does a major portion of the vent 14, and the vertical extension 1a. This heat dries out any wet trash, which is then ignited either by the heat of the housing 15 or by burner flames emerging from the openings in the housing 15. The products of combustion from the chamber can always escape up the chimney 1 either through the feedflue or, if this is blocked, through the corners of the chimney outside of the feed-flue.

In the conventional incinerator, it is not unusual for the incinerator to be packed with a large quantity of garbage, tin cans, etc., so that when the incinerator is fired to burn this material, the smoke and fumes from this combustion cannot escape through the chimney and will back up into the incinerator and out through the ash pit into the basement where the incinerator is located, creating not only a sanitary and health problem, but a fire hazard and a nuisance.

My invention does away with the nuisance mentioned in the preceding paragraph by always providing a by-pass around any obstruction in the feed-flue, so that the products of combustion do not back up in the incinerator. Damp, or wet garbage, or refuse emptied into the incinerator, may be slowly dried or dehydrated by means of the burner Within the perforated housing 15, so that the trash will burn gradually as it is emptied into the incinerator and it will not accumulate, or pack into the combustion chamber for burning as is done in the conventional incinerator. Also, such burner, being positioned as described, permits of its being burned with a low flame, sufiicient to dispose of garbage and other combustible as it is emptied into the incinerator, yet without any danger of being smothered or extinguished by such garbage or refuse.

My invention also operates in such a way that practically no smoke is emitted from the top of the chimney or feed flue and fly ash is tremendously reduced. The temperature of the furnace and chimney is always held at a lower and safe temperature. My invention provides positive ventilation for the ash pit and the combustion chamber at all times. It also provides a much increased, if not doubled, capacity in the disposal of garbage and trash fed into an incinerator of given dimension.

Another embodiment of my invention is shown in Figs. 5 to 8 inclusive. Here the furnace 17 is provided with a chimney 18 leading upwardly therefrom and having the usual fire brick lining 19. The top of the chimney is provided with a spark arrester 20. The chimney bypass 21 is here provided in one corner of the chimney by a strip of coarse Wire screen 22 bent arcuately through about 9ft degrees and held in position by lag bolts 23. This screen 22 extends from the combustion chamber all the way up to the top of the chimney or at least above the uppermost feed hopper 24 for feeding of trash into the feed-flue.

A burner housing 25 extends horizontally entirely across the furnace chamber 17 and directly above the grates 26, which are of the dumping type as shown in Figs. 7 and 8. The burner housing 25 is located so close to the plane of the grates 26 that it gets cooling airfrom the ash pit 29, which prevents the burner housing 25 from being damaged by the high temperatures in the combustion chamber. These grates dump in the direction of the small arrows shown in Fig. 8 and it will be seen that this in no way causes the grates to engage the housing 25. This housing 25 is set firmly in the masonry or it may be welded or otherwise attached to the grate frame at the front and rear of the chamber 17. The upper wall of the burner housing is perforated as shown at 25a. The lower side of the housing is provided with an elongated slot 25b as clearly shown in Fig. 8. The rear end of the housing '25 communicates with a vertical vent 27 which is here built within the masonry of the furnace lining so as to protect it from the heat of the furnace, a disadvantage of the vent 14 shown in my first described embodiment. In old installations a vent like 14 made of heat resisting material may be attached to the rear wall of chamber 17. The vent outlets to the chimney are shown at 27a and are located well above any expected height of trash piled in the incinerator. These vent outlets are nearer to the level of the bottom of the chimney flue than to the level of the grate. The lower end of vent 27 communicates through housing 25 and 25b with a small chute 28 formed in the masonry. This chute 28 makes the vent and the rear end of the housing 25 self-cleaning. At the same time, it provides a vent from the ash pit 29 through hute 28, housing 25 and vent 27 so that no pressure can build up in the ash pit.

The means here provided for heating the housing 25, comprises an elongated burner pipe 30, located centrally of the housing 25 and extending substantially to the rear wall of the incinerator chamber 17. This burner is supplied with a suitable fuel through pipe 31 under the control of valve 32 under control of safety pilot and safety solenoid shut-off valve, not shown. A suitable mixer is provided at the entrance end of the burner and suitable safety pilot equipment shown at 33. The burner pipe has a plurality of openings 3% through which the flame emerges.

The operation of this embodiment is similar to that first described. The fuel supply in pipe 31 is first turned on by means of valve 32. The safety pilot equipment at 33 operates in the usual manner whereby a safety pilot must first heat up a thermostat which then opens a solenoid valve allowing fuel to flow to the burner. The burner is then lit at the various openings 39a. The entire pipe 25 becomes hot and this, together with the flame emerging from the openings 25a, dries out the trash lying on top of the grates 26 and around the housing 25. The trash is ignited and burned and the products of combustion may always escape up the chimney, because, even though trash entering through the hoppers 24 may plug that portion of the chimney to the left and below the screen 22 shown in Fig. 6, the by-pass 21 always remains open for the escape of the products of combustion. Furthermore, the products of combustion of burner 30 are always carried away through vent 27 and the ash pit 29 is also vented by this means. It will be noted, that the burner housing 25 is located directly above the opening between the two grates as viewed in Figs. 7 and 8, this permits the cool air from the ash pit to engage against the lower side of the housing 25 so that the housing and burner 39 seldom become hot enough to destroy the metal.

Another form of dehydrator housing, burner and vent are shown in Fig. 9. Here the dehydrator housing 35 is a cylindrical tube firmly embedded in the masonry 36 of the wall of furnace 37 at both the front and rear wall of the incinerator. The upper part of the housing 35 is perforated as shown at 35a and the lower side is provided with a slot 35b similar to the slot 25]) previously described. The burner pipe 38 extends longitudinally of housing 35 and is equipped with a large number of individual burners 39 of a known type. The fuel supply is through pipe 40 under suitable controls, the safety valve and thermostat being within the housing 41 and being of conventional character. The housing 35 is adjacent and directly above the grates 42 which are of the dumping type, similar to the grates 26 already described. A vent pipe 43 is provided communicating with the upper rear portion of the housing 35. The openings 43 communicate with the chimney wall above any expected load of trash piled on the grates 42. The opera.

tion of this form of my invention is similar to that already described.

In Fig. 10, I show another dehydrator housing 45 having its front and rear end embedded in the masonry 46 of the incinerator chamber. The housing 45 could be attached to the grate frame. The upper wall of the housing is perforated as indicated at 45a and the lower wall of the housing 45 is either perforated or slotted as already taught in previous embodiments so that anything falling upon the housing 45, if it passes through the slots 45a, will drop clear of the housing 45 to the grates below. The new embodiment in Fig. involves the source for heating the housing '55. This is an electric heating element 47 of hair pin character connected with a source of electricity as indicated at 48 and 49. This embodiment operates similar to my previous ernbodiments in that the entire housing is heated by the electric resistance heating element 47 which is practically red hot. Combustibles start to burn either by contact with the hot housing 45 or by falling through and touching the heated element 47.

In Figs. 11, 12 and 16, I show a form of burner housing adapted to increase the area for dehydrating the trash, while at the same time permitting the dumping of grates.

The central housing in Fig. 11 has a flat top 5112 and arcuate sides extending downwardly and converging inwardly below the top portion. Between the lower ends of the sides 51]) there is a slotted opening 52. The top and side walls of the housing are perforated or slotted as indicated at 53. An electrical heating element of hair pin form is indicated at 54 and is suitably held within the housing 51a, 51b by braces not shown. The grates 55 oscillate about their pivot points 55 in the direction of the small arrow shown in Fig. 11. The side walls 51b are curved about the centers 55' so as to permit dumping movement of the grates without interference with the dehydrator housing. The side housings 56 are similar to the central housing except that they have one flat imperforate side 560 at right angles to the top 56a so as to attach the housing 56 to the masonry wall of the furnace. The arcuate wall 56b extends downwardly and converges inwardly toward the wall 560, leaving an open slot 57 at the bottom. Perforations 58 are provided in the top and side walls for the same purpose as the perforations 53.

The burner housing 59 shown in Fig. 12 is similar to the central housing in Fig. 11 except that it provides two shelves. The top shelf 60 is substantially flat and has below it side walls 61 which converge inwardly and downwardly. An electrical heating element 62 of hair pin type is suitably supported closely below the top 60. The side walls 61 do not come together but leave a slotted opening 63 from which the lateral shelves 64 extend horizontally outwardly to a distance beyond the shelf 60. Below the shelves 64 there are downwardly and inwardly converging arcuate walls 65 which do not quite meet at the bottom but leave a slotted opening 66. A hair pin electric heating element 67 is provided with one of its legs lying beneath each of the shelves 64. This burner housing 59 may have the portions 60, 61, 64 and 65 slotted. On the other hand, it might be used without slots if the heating elements 62 and 67 are sufficiently powerful to heat the shelves 60 and 64 for trash ignition. This will dry the combustible trash and also set it on fire. It will be understood that the dehydrator housing 59 would be connected across the central portion of anincinerator chamber with its opposite ends embedded in the masonry or attached to the grate frame.

Another modification is shown in Figs. 15 and 16. Here the dehydrator housing 68 is telescopic so that one size of housing may accommodate itself to incinerator chambers of different width. An end portion 69, and the opposite end portion are embedded in the masonry 71. of the front and rear furnace walls or attached to the grate frame, front and rear. A central section 72 is of the same general contour as the parts 69 and 70 but of slightly greater dimension so as to telescopically slide over them. The sectional view in Fig. 16 shows the member 72 on the outside and the member 69 on the inside. In the form here shown, each section has a flat top portion A and arcuate side portions B extending inwardly and downwardly therefrom, leaving an open slot C at the bottom of the housing for the purpose previously described. If the grates are sufficiently spaced, the side portions B need not converge downwardly. In order to eliminate the necessity of accurately aligning holes or openings in the top portions of the various parts of the housing, I have provided longitudinally extending slots 6% and 70a in the parts 69 and 70 respectively, and transverse slots 72a in the portion 72. These slots are of suflicient extent that the portions of them are bound to come into alignment with the parts are assembled as shown in Fig. 15 so as to provide openings in the top of the housing 68, The housing is provided with a vent 73 for the same purpose as the vents 14, 27, 43 and 50 previously described. Any form of heat may be provided within the housing 68, either a fuel burner or an electric heating element as previously described.

Still another modification of my invention is shown in Figs. 13 and 14. This is a multiple pass dehydrator housing in which the hot gases pass in the direction of the arrows of Fig. 13 first rearwardly in the cylindrical housing 74, then forwardly in the trapezoidal housing 75 and then rearwardly in the pentagonal housing 76, eventually passing up the vent tube 77. Communicating passageways are shown at 78 between 74 and 75, and at 79 between 75 and 76. The housing 74 extends generally horizontally across the incinerator chamber 80 and just above the grates 81. A supply pipe 82 for fuel leads to a burner 83 located centrally of the housing 74. This burner pipe may be of any of the types previously described herein. Preferably, but not necessarily, baffles 84 and 85 are provided on the lower and upper walls of housing 74 respectively so as to cause a longer travel of gases through the housing 74 to retain more of the heat for dehydration purposes. It will be noted that the upper walls 76a of housing 76 are sloped so that the trash will slide off of them. The upper walls 751: of the housing 75 provide a shelf for heating trash. Some or all of the walls of the housing 74, 75 and 76 may be perforated if desired.

What is claimed is:

1. Incinerator structure comprising walls forming a combustion chamber, a chimney flue extending upwardly from and in communication with said chamber, there being a closable opening leading into said flue above said combustion chamber for the introduction of rubbish or the like, a horizontally extending elongated heat conducting housing extending across said combustion chamber and spaced below said chimney flue, means for heating said housing, spaced grates each of which extends a substantial distance beneath said housing and extending laterally thereof and forming a bottom for said combustion chamber, said housing being disposed over the space between said grates and an ash pit below said grates, said spacing between said grates being less than the greatest width of said housing.

2. The combination of claim 1 including means forming a by-pass vent passage communicating between said ash pit and a Zone in said combustion chamber nearer to the level of the bottom of said flue than to the level of said grate.

3. The combination of claim 1 wherein said housing extends substantially entirely across said combustion chamber, and said heating means comprises a fuel burner contained within said housing and extending substantially the entire length of said housing.

4. The combination of claim 1 wherein said housing extends substantially entirely across said combustion chamher, and said heating means comprises an electric heating element extending substantially the entire length 01 said housing.

5. The combination of claim 1 wherein said housing is wider at the top than at the bottom, as viewed in trans verse section.

6. The combination of claim 1 wherein said housing has a generally flat top and side walls converging inwardly and downwardly therefrom.

7. The combination of claim 6 wherein there is a space between the bottom edges of said side walls.

8. The combination of claim 7 wherein said grate comprises two grate portions substantially co-planar and spaced apart laterally, said space between the bottom edges of said side walls is directly above said space between said grate portions, and the bottom of said housing is close to the level of said grate portions.

9. The combination of claim 1 wherein said grate comprises two dumping grate portions substantially co-planar and spaced apart laterally, each of said grate portions having a pivotal axis generally parallel to the longitudinal dimension of said housing, and said housing comprises a generally flat top and side walls converging inwardly and downwardly therefrom, said side walls being arcuat'e and just clearing the peripheral edge of a grate portion oscillating about its pivotal axis.

10. The combination of claim 1 wherein said housing comprises a hollow upper portion having an open slot extending along substantially the entire bottom of said portion, a hollow lower portion having a top wall wider than said upper portion, said slot providing communication between said upper and lower portions, and said lower portion having an open bottom.

11. The combination of claim 1 wherein said housing comprises a plurality of generally parallel hollow housing portions, there being a communicating passage between adjacent ends of said portions, the other end of one portion communicating with a source of air for heating, and the other end of said other portion communicating with said chimney flue.

12. The combination of claim 1 wherein said grate comprises two grate portions substantially co-planar and spaced apart laterally, and said housing has an open bottom directly above said space between said grate portions and close to the level of said grate portions.

13. Incinerator structure comprising walls forming a combustion chamber, a chimney, a flue in communication between said chamber and chimney, a horizontally extending elongated heat conducting housing extending across said chamber and below said flue communication, combustible gas means for heating said housing to a trash ignition temperature, a grate below said housing and laterally to at least one side thereof and forming a bottom for said chamber, means for pivoting said grate .about a pivot axis, said housing being spaced above said grate a distance wherein the minimum distance between the outer surface of said housing and grate pivot axis is greater than the distance between said grate pivot axis and the inner edge of said grate, there being a door opening through a wall of said chamber above said grate and a door for closing the same, and means forming a vent extending upwardly from said housing to a zone above said door opening, there being means forming an opening at the top of said vent, whereby gas in said housing can always escape to said flue even When trash is piled in said chamber up to the level of said door.

14. Incinerator structure comprising walls forming a combustion chamber, a chimney flue extending upwardly from and in communication with said chamber, there being a closable opening leading into said flue above said combustion chamber for the introduction of rubbish or the like, a horizontally extending elongated heat conducting housing extending across said combustion chamber and spaced below said chimney flue, means for heating said housing, spaced grates underlying said housing and extending laterally thereof and forming a bottom for said combustion chamber, means associated with said grates for pivoting said grates about a pivot axis, said housing being spaced above said grates .a distance wherein the minimum distance between the outer surface of said housing and each grate pivot axis is greater than the distance between said grate pivot axis and the inner edge of each grate, and an ash pit below said grates.

15. Incinerator structure comprising walls forming a. combustion chamber, a chimney flue extending upwardly from and in communication with said chamber, there being a closable opening leading into said flue above said combustion chamber for the introduction of rubbish or the like, a horizontally extending elongated heat conducting housing extending across said combustion chamber and spaced below said chimney flue, means for heating said housing, spaced grates each of which extends a substantial distance beneath said housing and extending laterally thereof and forming a bottom for said combustion chamber, said housing being disposed over the space between said grates, and an ash pit below said grates, said spacing between said grates being less than the greatest width of said housing, means forming a bypass vent passage communicating between said housing and a zone in said combustion chamber nearer to the level of the bottom of said flue than to the level of said grate, means forming an inclined passage leading from said housing directly below said vent passage to said ash pit, whereby loose material may fall from said vent passage into said pit and whereby said ash pit is vented above the expected level of rubbish in said chamber.

References Cited in the file of this patent UNITED STATES PATENTS 178,372 Kidder June 6, 1876 1,156,691 Kahn Oct. 12, 1915 1,218,325 Shannon Mar. 6, 1917 1,428,782 Jouclard Sept. 12, 1922 1,608,312 Goodenow Nov. 23, 1926 1,674,304 Sharnberg June 19, 1928 1,724,575 Graver Aug. 13, 1929 1,772,718 Howle Aug. 12, 1930 

